Fume Hood Specifications

• A fume hood is a piece of lab equipment that can keep you safe when working with dangerous or radioactive materials. The type of hood that's appropriate for your lab depends on the amount of space you can dedicate to it, and the range of hazardous materials you typically handle. However, most fume hoods share a few basic features.

Construction Materials

• Fume hoods should always be made from nonflammable materials. The floor should comprise sealed rock or a poly-resin coating, as these materials are generally impervious to spilled chemicals. They also allow for easy clean-up in case a spill occurs. The preferred hood face is a thick, flame-retardant plastic that will protect the user from inadvertent fires, violent reactions and chemical spills.

Sash Specifications

• The sash is the door that slides up and down on the face of the fume hood. Keep the sash height at 18 inches while working in the hood. If necessary, place stoppers at this point to keep the hood in the correct place. You should only open the sash fully when placing equipment inside the hood. Horizontal sashes are also available to keep you a predetermined distance from the hood opening. This protects you from dangerous substances, and is particularly useful when working with radioactive materials. When the sash is fully closed, the hood interior should be airtight.

Internal Features

• The interior of the hood may have air (or vacuum), gas and water hookups. Many experiments require these tools, which are especially important for dangerous or sterile procedures. If the fume hood includes a full sink, it should have an elevated lip to prevent flooding onto the hood floor. Interior lights have external switches, as do optional ultraviolet (UV) lights used for sterilization. Some hood interiors also come equipped with electrical outlets for various types of equipment. However, exterior outlets are safer.

Ventilation

• All fume hoods connect to duct work that leads outside of the building. Appropriate materials for ducts include stainless steel and polyvinyl-coated galvanized steel. Ducts and vents should be dent-free and have minimal scratches. It's also important to bring enough additional air into the room to make up for the amount the hood vents as exhaust.

Additional Features

• Some fume hoods come with audio or visual alarms, and other safety features. If the airflow backs up or shuts down, the alarm will alert you to the problem. Many hoods that come with gas valves or water also have emergency shutoff mechanisms. Other common features include under-hood storage cabinets, and timers for UV lights.